package 笔试.阿里;

import java.util.Scanner;

/**
 * @author:谢君臣
 * @Date:2021/9/3-19:30
 * @version:1.0
 * @function:
 */
public class Main02 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        double a = scanner.nextDouble();
        double b = scanner.nextDouble();
        double c = scanner.nextDouble();
        double i =  Math.sqrt(a);
        double j =  Math.sqrt(a);
        long count = 0;
        for (;i<Math.sqrt(b);i++){
            for (;j*j*j<b;j++)
                if (Math.abs(i*i-j*j*j)<=c) count++;
        }
        String res = String.valueOf(count);
        System.out.println(res.substring(0,res.length()-2));
    }
}
